/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.catalina.util;

import org.apache.tomcat.util.buf.ByteChunk;
import org.apache.tomcat.util.buf.CharChunk;

import javax.xml.bind.DatatypeConverter;

/**
 * This class provides encode/decode for RFC 2045 Base64 as defined by
 * RFC 2045, N. Freed and N. Borenstein.  <a
 * href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>:
 * Multipurpose Internet Mail Extensions (MIME) Part One: Format of
 * Internet Message Bodies. Reference 1996
 *
 * @author Jeffrey Rodriguez
 * @deprecated Use {@link org.apache.tomcat.util.codec.binary.Base64}
 * This class will be removed in Tomcat 8.
 */
@Deprecated
public final class Base64 {
	private static final int BASELENGTH = 255;
	private static final int LOOKUPLENGTH = 64;
	private static final int FOURBYTE = 4;
	private static final byte PAD = (byte) '=';
	private static final byte[] base64Alphabet = new byte[BASELENGTH];
	private static final byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];

	static {
		for (int i = 0; i < BASELENGTH; i++) {
			base64Alphabet[i] = -1;
		}
		for (int i = 'Z'; i >= 'A'; i--) {
			base64Alphabet[i] = (byte) (i - 'A');
		}
		for (int i = 'z'; i >= 'a'; i--) {
			base64Alphabet[i] = (byte) (i - 'a' + 26);
		}
		for (int i = '9'; i >= '0'; i--) {
			base64Alphabet[i] = (byte) (i - '0' + 52);
		}

		base64Alphabet['+'] = 62;
		base64Alphabet['/'] = 63;

		for (int i = 0; i <= 25; i++)
			lookUpBase64Alphabet[i] = (byte) ('A' + i);

		for (int i = 26, j = 0; i <= 51; i++, j++)
			lookUpBase64Alphabet[i] = (byte) ('a' + j);

		for (int i = 52, j = 0; i <= 61; i++, j++)
			lookUpBase64Alphabet[i] = (byte) ('0' + j);

		lookUpBase64Alphabet[62] = (byte) '+';
		lookUpBase64Alphabet[63] = (byte) '/';
	}

	/**
	 * Encodes hex octets into Base64.
	 *
	 * @param binaryData Array containing binary data to encode.
	 * @return Base64-encoded data.
	 * @deprecated Use {@link DatatypeConverter#printBase64Binary(byte[])}.
	 * This method will be removed in Tomcat 8.0.x.
	 */
	@Deprecated
	public static String encode(byte[] binaryData) {
		return DatatypeConverter.printBase64Binary(binaryData);
	}

	/**
	 * Decodes Base64 data into octets
	 *
	 * @param base64DataBC  Byte array containing Base64 data
	 * @param decodedDataCC The decoded data chars
	 */
	public static void decode(ByteChunk base64DataBC, CharChunk decodedDataCC) {
		int start = base64DataBC.getStart();
		int end = base64DataBC.getEnd();
		byte[] base64Data = base64DataBC.getBuffer();

		decodedDataCC.recycle();

		// handle the edge case, so we don't have to worry about it later
		if (end - start == 0) {
			return;
		}

		int numberQuadruple = (end - start) / FOURBYTE;
		byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;

		// Throw away anything not in base64Data

		int encodedIndex = 0;
		int dataIndex = start;
		char[] decodedData = null;

		{
			// this sizes the output array properly - rlw
			int lastData = end - start;
			// ignore the '=' padding
			while (base64Data[start + lastData - 1] == PAD) {
				if (--lastData == 0) {
					return;
				}
			}
			decodedDataCC.allocate(lastData - numberQuadruple, -1);
			decodedDataCC.setEnd(lastData - numberQuadruple);
			decodedData = decodedDataCC.getBuffer();
		}

		for (int i = 0; i < numberQuadruple; i++) {
			dataIndex = start + i * 4;
			marker0 = base64Data[dataIndex + 2];
			marker1 = base64Data[dataIndex + 3];

			b1 = base64Alphabet[base64Data[dataIndex]];
			b2 = base64Alphabet[base64Data[dataIndex + 1]];

			if (marker0 != PAD && marker1 != PAD) {
				//No PAD e.g 3cQl
				b3 = base64Alphabet[marker0];
				b4 = base64Alphabet[marker1];

				decodedData[encodedIndex] = (char) ((b1 << 2 | b2 >> 4) & 0xff);
				decodedData[encodedIndex + 1] =
						(char) ((((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)) & 0xff);
				decodedData[encodedIndex + 2] = (char) ((b3 << 6 | b4) & 0xff);
			} else if (marker0 == PAD) {
				//Two PAD e.g. 3c[Pad][Pad]
				decodedData[encodedIndex] = (char) ((b1 << 2 | b2 >> 4) & 0xff);
			} else if (marker1 == PAD) {
				//One PAD e.g. 3cQ[Pad]
				b3 = base64Alphabet[marker0];

				decodedData[encodedIndex] = (char) ((b1 << 2 | b2 >> 4) & 0xff);
				decodedData[encodedIndex + 1] =
						(char) ((((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)) & 0xff);
			}
			encodedIndex += 3;
		}
	}

	/**
	 * Decodes Base64 data into octets
	 *
	 * @param base64DataBC  Byte array containing Base64 data
	 * @param decodedDataBC The decoded data bytes
	 */
	public static void decode(ByteChunk base64DataBC, ByteChunk decodedDataBC) {
		int start = base64DataBC.getStart();
		int end = base64DataBC.getEnd();
		byte[] base64Data = base64DataBC.getBuffer();

		decodedDataBC.recycle();

		// handle the edge case, so we don't have to worry about it later
		if (end - start == 0) {
			return;
		}

		int numberQuadruple = (end - start) / FOURBYTE;
		byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;

		// Throw away anything not in base64Data

		int encodedIndex = 0;
		int dataIndex = start;
		byte[] decodedData = null;

		{
			// this sizes the output array properly - rlw
			int lastData = end - start;
			// ignore the '=' padding
			while (base64Data[start + lastData - 1] == PAD) {
				if (--lastData == 0) {
					return;
				}
			}
			decodedDataBC.allocate(lastData - numberQuadruple, -1);
			decodedDataBC.setEnd(lastData - numberQuadruple);
			decodedData = decodedDataBC.getBuffer();
		}

		for (int i = 0; i < numberQuadruple; i++) {
			dataIndex = start + i * 4;
			marker0 = base64Data[dataIndex + 2];
			marker1 = base64Data[dataIndex + 3];

			b1 = base64Alphabet[base64Data[dataIndex]];
			b2 = base64Alphabet[base64Data[dataIndex + 1]];

			if (marker0 != PAD && marker1 != PAD) {
				//No PAD e.g 3cQl
				b3 = base64Alphabet[marker0];
				b4 = base64Alphabet[marker1];

				decodedData[encodedIndex] = (byte) ((b1 << 2 | b2 >> 4) & 0xff);
				decodedData[encodedIndex + 1] =
						(byte) ((((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)) & 0xff);
				decodedData[encodedIndex + 2] = (byte) ((b3 << 6 | b4) & 0xff);
			} else if (marker0 == PAD) {
				//Two PAD e.g. 3c[Pad][Pad]
				decodedData[encodedIndex] = (byte) ((b1 << 2 | b2 >> 4) & 0xff);
			} else if (marker1 == PAD) {
				//One PAD e.g. 3cQ[Pad]
				b3 = base64Alphabet[marker0];

				decodedData[encodedIndex] = (byte) ((b1 << 2 | b2 >> 4) & 0xff);
				decodedData[encodedIndex + 1] =
						(byte) ((((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)) & 0xff);
			}
			encodedIndex += 3;
		}
	}


}
